//The MIT License

//Copyright (c) 2009 Lluis Sanchez, Nick Darnell

//Permission is hereby granted, free of charge, to any person obtaining a copy
//of this software and associated documentation files (the "Software"), to deal
//in the Software without restriction, including without limitation the rights
//to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//copies of the Software, and to permit persons to whom the Software is
//furnished to do so, subject to the following conditions:

//The above copyright notice and this permission notice shall be included in
//all copies or substantial portions of the Software.

//THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//THE SOFTWARE.

using System;
using System.Reflection;
using System.Reflection.Emit;
using Polymorph.Properties;

namespace Polymorph
{
    public abstract class CodeBinaryComparison : CodeConditionExpression
    {
        protected CodeExpression m_exp1;
        protected CodeExpression m_exp2;
        protected Type m_t1;
        protected Type m_t2;

        private string m_symbol;

        public CodeBinaryComparison(CodeExpression exp1, CodeExpression exp2, string symbol)
        {
            m_symbol = symbol;
            m_exp1 = exp1;
            m_exp2 = exp2;

            m_t1 = exp1.ResultType;
            m_t2 = exp2.ResultType;

            if (!m_t1.IsPrimitive || !m_t2.IsPrimitive || (m_t1 != m_t2))
            {
                throw new InvalidOperationException(
                    string.Format(Resources.Operator0CanNotBeAppliedTo1And2,
                    GetType().Name, m_t1.Name, m_t2.Name));
            }
        }

        public override void PrintCode(CodeWriter cp)
        {
            m_exp1.PrintCode(cp);
            cp.Write(" " + m_symbol + " ");
            m_exp2.PrintCode(cp);
        }

        public override Type ResultType
        {
            get { return typeof(bool); }
        }
    }

    public class CodeGreaterThan : CodeBinaryComparison
    {
        public CodeGreaterThan(CodeExpression exp1, CodeExpression exp2)
            : base(exp1, exp2, ">")
        {
        }

        public override void Generate(ILGenerator gen)
        {
            m_exp1.Generate(gen);
            m_exp2.Generate(gen);
            gen.Emit(OpCodes.Cgt);
        }

        public override void GenerateForBranch(ILGenerator gen, Label label, bool branchCase)
        {
            m_exp1.Generate(gen);
            m_exp2.Generate(gen);
            if (branchCase)
                gen.Emit(OpCodes.Bgt, label);
            else
                gen.Emit(OpCodes.Ble, label);
        }
    }

    public class CodeGreaterEqualThan : CodeBinaryComparison
    {
        public CodeGreaterEqualThan(CodeExpression exp1, CodeExpression exp2)
            : base(exp1, exp2, ">=")
        {
        }

        public override void Generate(ILGenerator gen)
        {
            m_exp1.Generate(gen);
            m_exp2.Generate(gen);
            gen.Emit(OpCodes.Clt);
            gen.Emit(OpCodes.Ldc_I4_0);
            gen.Emit(OpCodes.Ceq);
        }

        public override void GenerateForBranch(ILGenerator gen, Label label, bool branchCase)
        {
            m_exp1.Generate(gen);
            m_exp2.Generate(gen);
            if (branchCase)
                gen.Emit(OpCodes.Bge, label);
            else
                gen.Emit(OpCodes.Blt, label);
        }
    }

    public class CodeLessThan : CodeBinaryComparison
    {
        public CodeLessThan(CodeExpression exp1, CodeExpression exp2)
            : base(exp1, exp2, "<")
        {
        }

        public override void Generate(ILGenerator gen)
        {
            m_exp1.Generate(gen);
            m_exp2.Generate(gen);
            gen.Emit(OpCodes.Clt);
        }

        public override void GenerateForBranch(ILGenerator gen, Label label, bool branchCase)
        {
            m_exp1.Generate(gen);
            m_exp2.Generate(gen);
            if (branchCase)
                gen.Emit(OpCodes.Blt, label);
            else
                gen.Emit(OpCodes.Bge, label);
        }
    }

    public class CodeLessEqualThan : CodeBinaryComparison
    {
        public CodeLessEqualThan(CodeExpression exp1, CodeExpression exp2)
            : base(exp1, exp2, "<=")
        {
        }

        public override void Generate(ILGenerator gen)
        {
            m_exp1.Generate(gen);
            m_exp2.Generate(gen);
            gen.Emit(OpCodes.Cgt);
            gen.Emit(OpCodes.Ldc_I4_0);
            gen.Emit(OpCodes.Ceq);
        }

        public override void GenerateForBranch(ILGenerator gen, Label label, bool branchCase)
        {
            m_exp1.Generate(gen);
            m_exp2.Generate(gen);
            if (branchCase)
                gen.Emit(OpCodes.Ble, label);
            else
                gen.Emit(OpCodes.Bgt, label);
        }
    }
}